Question

which of the following is not a form of electronic communication email,voice,cellular phone,vediomail

Answer 1

Answer:

Answer

We know that

sinx=

2

1

=sin

4

π

and by allied angles, we also know that

sin(π−x)=sinx

∴sin

4

π

=sin(π−

4

π

)=sin

4

3π

∴sin

4

π

=sin3π4=

2

1

such that 0<

4

π

<2π and 0<

4

3π

<2π

∴ the required principal solution are x=

4

π

and x=

4

3π

Answer 2

Answer:

cellular phone

Explanation:

cellular phone comes under mobile communication